Balers which are equipped with a binding apparatus in order to hold the crop pressed to form a bale together by wrapping a twine around it are known. Such binding apparatuses generally comprise a mechanically controlled binding twine guide in the form of one or more guide arms which guide the binding twine along the bale winding surface while the round bale is rotated. After completion of the binding operation, the binding twine has to be severed in order that the bale can leave the baling chamber. In order to sever the binding twine, use is made of cutting devices which are coupled to the guide arms and are guided in the direction of the binding twine after or during the binding operation. The cutting device generally comprises a cutting knife guide, for example in the form of a further guide arm, having a cutting knife holder in which a cutting knife is held. The guide arms are controlled such that, after completion of the binding operation, the cutting edge of the cutting knife comes into contact with the binding twine. Generally, the binding twine meets the cutting blade edge to edge and under low binding twine tension, thereby resulting in an inadequate cut surface of the binding twine and also in wear of the cutting knife and thus in a short service life. Furthermore, a poor cut surface on the binding twine can lead to fraying of the binding twine. As a result, the subsequent threading process for the new bale can be hindered, leading to interruptions in the bale-winding process and thus to increased expenditure of time.